Method of collecting information in mobile communication system

ABSTRACT

A mobile radio terminal includes a positional information acquisition unit to measure the position of the mobile radio terminal as position information using a Global Positioning System; a reception status acquisition unit to detect a handover failure; and a controller to send information of the position information and handover failure information to a base station.

This application is a Continuation application of U.S. patentapplication Ser. No. 10/700,483, filed on Nov. 5, 2003, which, in turn,has foreign priority based on Japanese Application No. 2002-330734,filed on Nov. 14, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a radio communication system, and moreparticularly to the collection of measured values of reception statusesfor the maintenance and optimization of a radio communication system.

2. Description of the Related Art

At present, efforts are being made to lower charges to be paid bysubscribers to radio communication systems such as cellular phonesystems, PHS, public radio LAN systems, etc. One of the efforts is tolower the operating costs of radio communication systems as much aspossible. It is a large task for communication service providers to makeless costly adjustments for the maintenance and optimization of radiocommunication systems.

The adjustments for the maintenance and optimization of radiocommunication systems include maintenance and adjustment activities thatare performed to operate the radio communication systems stably withoutsystem failures over a long period of time. Items that need to beadjusted include, for example, the transmission power level of a radiobase station and the tilt angle of an antenna.

The maintenance and adjustment of a radio communication system aregenerally performed based on an evaluation or examination process whichemploys a radio network design simulator. In order to increase theaccuracy of a simulation, information about reception statuses that aremeasured in service areas (hereinafter referred to as “coverages”) ofthe radio communication system and information about positions wheremeasured values are obtained are input to the design simulator.

In a CDMA system, for example, items of reception status informationinclude the received signal quality and received signal intensity of acommon pilot channel. These items of reception status information areuseful items indispensable for system maintenance and adjustmentsbecause they serve as indexes for determining whether the services ofthe radio communication system are available to mobile radio terminalsin the measured position or not.

Heretofore, it has been customary for a dedicated measuring vehicle or adedicated measuring team to measure reception status information. FIG. 1of the accompanying drawings is illustrative of a conventional processof collecting reception status information from a radio communicationsystem. According to the conventional process, as shown in FIG. 1,coverages of the radio communication system in which radio base stations91, 92, 93 are connected to network 90 are visited by members ofmeasuring teams with reception status measuring vehicles 94. At eachmeasuring spot, one reception status measuring vehicle 94 measuresreception status information in the corresponding coverage. The measuredreception status information is recorded in association with thepositional information that is measured by position measuring device 94a on reception status measuring vehicle 94.

Using the measured reception status information, the communicationservice provider performs maintenance and adjustments of the radiocommunication system to operate the radio communication system stablywithout fail.

According to another conventional process of collecting reception statusinformation, the general mobile radio terminal owned by a user is usedto measure reception status information, and the measured receptionstatus information is collected from the mobile radio terminal (see, forexample, JP2002-152104-A). According to this conventional process,reception status information can quickly and easily be collected withoutthe need for the reception status measuring vehicle shown in FIG. 1.

The above conventional processes suffer the following problems:

The process of measuring reception status information using receptionstatus measuring vehicles 94 shown in FIG. 1 needs a measuring team ofmembers including a vehicle driver, a navigator, and a measuring personfor driving each reception status measuring vehicle 94 and makingmeasurements at desired spots. Expenses required to purchase andmaintain the measuring vehicles and personnel expenses required tocollect reception status information are large and present an obstacleto efforts to lower the operating cost of the radio communicationsystem. The conventional process shown in FIG. 1 takes a lot of time tocollect reception status information because all the coverages of theradio communication system need to be visited by a limited number ofreception status measuring vehicles.

Reception status information in the coverages may be measured by manymeasuring teams without reception status measuring vehicles 94. However,such a modification requires increased labor costs though receptionstatus measuring vehicles 94 are dispensed with.

In a CDMA radio communication system, when users are connected to thesystem, the load on the radio communication system, i.e., aninterference quantity, changes, and hence coverages of the radiocommunication system vary with time. In order to keep stable coverageswhile the number of users is being progressively grown to turn thesystem into a mature one, it is necessary to repeatedly collectreception status information periodically. Consequently, the CDMA radiocommunication system requires a much greater cost for collectingreception status information than other systems because reception statusmeasuring vehicles need to travel repeatedly periodically for collectingreception status information.

Another problem of the CDMA radio communication system is that whilereception status information is being measured by reception statusmeasuring vehicles as they travel through coverages, the user status inthe measured areas may change.

According to the process of collecting reception status information withthe general mobile radio terminals owned by users as disclosed inJP2002-152104-A, reception status information can be collected at a lowcost because no reception status measuring vehicles and no measuringteams of various members are required. Since the coverages of the radiocommunication system are not visited by reception status measuringvehicles, but reception status information is measured by the mobileradio terminals owned by general users, a large amount of receptionstatus information can be collected in a short period of time.

In the CDMA radio communication system, however, the reception statuschanges for various reasons, and changes in the reception status affectthe operation of the radio communication system in various ways. Forexample, the reception status may change either with time or as thesystem load changes due to a user access congestion. Changes in thereception status may cause a change in the frequency of forcedcommunication shutdowns from the network or a change in the frequency ofhandover failures.

The process disclosed in JP-2002-152104-A serves to collect only therelationship between reception status information and positionalinformation, but fails to appropriately recognize causes of changes inthe reception status and phenomena brought about by changes in thereception status.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodof and a system for, and a mobile radio terminal for, collectinginformation related to operation of a radio communication systeminexpensively and easily.

To achieve the above object, an information collecting system accordingto the present invention collects information used for adjustments in aradio communication system for performing user communications.

At least one mobile radio terminal monitors a communication status ofuser communications. When the mobile radio terminal detects as a triggerwhen the communication status has satisfied a predetermined condition,the mobile radio terminal acquires a reception status of a radio signaland the position of its own. The mobile radio terminal sends measuredinformation including the reception status and the position to aninformation collecting server. The information collecting serverreceives the measured information from the mobile radio terminal andrecords therein the measured information which has been received.

Therefore, the communication service provider of the radio communicationsystem can instantaneously obtain many reception statuses in respectivepositions in coverages in relation to the communication status, and caninstantaneously and effectively perform maintenance and adjustments ofradio communication facilities. Thus, man-hours and expenses involved incollecting information can be reduced.

Instantaneous and accurate system adjustments are significant in an areawhere many users are present. According to the present invention, manyitems of measured information of such an area are obtained, making itpossible to make instantaneous and accurate system adjustments using mayitems of measured information in an area where the need for systemadjustments is high.

In another information collecting system according to the presentinvention, an information collecting server sends trigger informationsimultaneously to at least one mobile radio terminal. When the mobileradio terminal receives the trigger information as a measuring trigger,the mobile radio terminal acquires a reception status of a radio signaland the position of its own. The mobile radio terminal sends measuredinformation including the reception status and the position to aninformation collecting server. The information collecting server recordsthe measured information received from the mobile radio terminal.

Accordingly, many items of measured information at respective spots atthe same time can instantaneously be obtained for instantaneously andeffectively performing maintenance and adjustments of radiocommunication facilities.

In still another information collecting system according to the presentinvention, an information collecting server sends trigger informationsimultaneously to at least one mobile radio terminal. The mobile radioterminal monitors a communication status of user communications. Whenthe mobile radio terminal detects as a trigger when the communicationstatus has satisfied a predetermined condition, or receives the triggerinformation as a measuring trigger, the mobile radio terminal acquires areception status of a radio signal and the position of its own. Themobile radio terminal sends measured information including the receptionstatus and the position to an information collecting server. Theinformation collecting server records the measured information receivedfrom the mobile radio terminal.

The above and other objects, features, and advantages of the presentinvention will become apparent from the following description withreference to the accompanying drawings which illustrate examples of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrative of a conventional process ofcollecting reception status information from a radio communicationsystem;

FIG. 2 is a schematic view of a radio communication system according toan embodiment of the present invention;

FIG. 3 is a block diagram of a mobile radio terminal according to theembodiment of the present invention;

FIG. 4 is a flowchart of an operation sequence of the radiocommunication system and the mobile radio terminal according to theembodiment of the present invention for collecting reception statusinformation;

FIG. 5 is a block diagram of a mobile radio terminal according toanother embodiment of the present invention;

FIG. 6 is a flowchart of an operation sequence of the radiocommunication system and the mobile radio terminal according to theother embodiment of the present invention for collecting receptionstatus information;

FIG. 7 is a block diagram of a mobile radio terminal according to stillanother embodiment of the present invention; and

FIG. 8 is a flowchart of an operation sequence of the radiocommunication system and the mobile radio terminal according to thestill other embodiment of the present invention for collecting receptionstatus information.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described indetail below.

FIG. 2 schematically shows a radio communication system according to anembodiment of the present invention. As shown in FIG. 2, the radiocommunication system has radio base stations 11, 12, 13, network 2, andinformation collecting server 1. Mobile radio terminals 21, 22 can beconnected to the radio communication system. In FIG. 2, only two mobileradio terminals are shown though many mobile radio terminals canactually be connected to the radio communication system. Actually, theradio communication system has many radio base stations, but only threeradio base stations are shown in FIG. 2 for illustrative purposes.

Mobile radio terminals 21, 22 comprise mobile terminals of cellularphone systems, PHS, public radio LAN systems, etc. that users use in theradio communication system. The users who use mobile radio terminals 21,22 are users who have consented to provide information about their ownpositions and the reception status of radio signals from radio basestations for stable operation of the radio communication system.

FIG. 3 shows in block form details of mobile radio terminal 21 accordingto the present embodiment. Since mobile radio terminals 21, 22 areidentical in arrangement, only mobile radio terminal 21 is shown in FIG.3.

As shown in FIG. 3, mobile radio terminal 21 comprises positionalinformation acquisition unit 31, reception status acquisition unit 32,communication status acquisition unit 33, time information acquisitionunit 34, control unit 35, and display unit 36.

Positional information acquisition unit 31 acquires informationrepresentative of the position of mobile radio terminal 21. Positionalinformation acquisition unit 31 measures its own position using a GPS(Global Positioning System), for example, and acquires the measuredposition as the positional information.

Reception status acquisition unit 32 acquires information representativeof the reception status of a radio signal from a radio base station. Theinformation representative of the reception status, i.e., the receptionstatus information, is useful for the maintenance and adjustments of theradio communication system. Examples of the reception status informationare Ec/Io (received signal power vs. interference power ratio per chip)indicative of a received signal quality of a common pilot channel in aCDMA radio communication system, and a received signal intensity in sucha common pilot channel.

Communication status acquisition unit 33 can acquire informationrepresentative of the communication status of user communications. Theinformation representative of the communication status, i.e., thecommunication status information, is information indicative of thestatus of communications that are performed using a radio signal.Examples of the communication status information are informationindicating that the mobile radio terminal is unable to receive a radiosignal from a radio base station and user communications are forciblyshut off, and information indicating that the mobile radio terminal isunable to make an outgoing call to another mobile radio terminal. Otherexamples of the communication status information are informationindicating a handover failure and information indicating a communicationthroughput.

Time information acquisition unit 34 can acquire informationrepresentative of the time when reception status information isacquired, time information representative of the time when a receptionstatus has started to be measured, and time information representativeof the period of time for which a reception status has been measured.

When positional information, time information, and reception statusinformation are acquired, control unit 35 sends the acquired informationas measured information through either one of the radio base stationsand network 2 to information collecting server 1. The measuredinformation is information that includes positional information, timeinformation, and reception status information.

When communication status information acquired by communication statusacquisition unit 33 satisfies a predetermined condition, control unit 35is triggered to instruct reception status acquisition unit 32 to acquirereception status information, instruct positional informationacquisition unit 31 to acquire positional information, and instruct timeinformation acquisition unit 34 to acquire a measuring start time and ameasuring period of time. For example, when user communication such as acall or data communication are forcibly shut off, mobile ratio terminal21 is triggered to acquire reception status information. Alternatively,mobile ratio terminal 21 may be triggered to acquire reception statusinformation when the communication throughput becomes lower than apredetermined threshold value, or when a call is made to start usercommunications.

When control unit 35 receives information representative of a valuablepoint from information collecting server 1, control unit 35 displays thevaluable point on display unit 36.

The valuable point is a point having a value corresponding to money, andis given to a user in return for the measured information provided bythe user. An example of the valuable point is a point that can be usedin electronic commerce on the Internet that is included in network 2.Another example of the valuable point is any of various cybercash andelectronic money. Still another example of the valuable point is a pointhaving a value in a core network of the radio communication system whichis included in network 2, i.e., a point that can be used to offset acharge to be paid for using the radio communication system.

Display unit 36 displays valuable point information according to aninstruction from control unit 35.

Radio base stations 11, 12, 13 are facilities for sending radio signalsto and receiving radio signals from mobile radio terminals 21, 22, andcomprise base stations in cellular phone systems or PHSs, or accesspoints of radio LAN systems or the like.

Network 2 comprises a core network of the radio communication systemaccording to the present embodiment, e.g., a network made up of mobileexchanges of a cellular phone system. In the present embodiment, network2 also includes the Internet connected through a gateway (not shown).

Information collecting server 1 comprises a computer such as aworkstation or the like. Information collecting server 1 receives andrecords measured information transmitted from mobile radio terminals 21,22. When information collecting server 1 receives and records measuredinformation transmitted from mobile radio terminals 21, 22, informationcollecting server 1 sends valuable point information that is to be givento the users of mobile radio terminals 21, 22, i.e., transmissionsources, through network 2 and a radio base station to mobile radioterminals 21, 22.

FIG. 4 shows an operation sequence of the radio communication system andthe mobile radio terminal according to the present embodiment forcollecting reception status information. In FIG. 4, operation of onlymobile radio terminal 21 and information collecting server 1 isillustrated.

Dedicated software is installed beforehand in the mobile radio terminalof a user who has consented to provide measured information includinginformation about reception status information and positionalinformation in return for the acquisition of a valuable point. Themobile radio terminal with the dedicated software installed is used asmobile radio terminals 21, 22. With the dedicated software installed,mobile radio terminals 21, 22 can automatically operate as follows:

As shown in FIG. 4, mobile radio terminal 21 monitors the communicationstatus of user communications, and detects as a trigger whencommunication status information has satisfied a predetermined condition(step 101). When mobile radio terminal 21 detects the trigger, mobileradio terminal 21 measures a reception status and acquires receptionstatus information indicative of the measured reception status (step102). At this time, mobile radio terminal 21 also acquires timeinformation. Instead of the operation in steps 101, 102, mobile radioterminal 21 may continuously measure a reception status at all timesand, when mobile radio terminal 21 detects a trigger, it may use thereception status measured at the time for a subsequent process.

Then, mobile radio terminal 21 measures its own position using a GPS,and acquires positional information indicative of the measured position(step 103). However, mobile radio terminal 21 may not be able to acquirepositional information depending on its position or environment. In thatcase, mobile radio terminal 21 may use positional information which ithas acquired at a past time closest to the present time. Moreover,mobile radio terminal 21 should preferably add information indicative oflow reliability to the positional information. Then, mobile radioterminal 21 sends measured information including the positionalinformation, the time information, and the reception status informationto information collecting server 1 (step 104).

In order to reflect the measured information early for systemadjustments, mobile radio terminal 21 should preferably send themeasured information including the reception status information and thepositional information to information collecting server 1 immediatelyafter mobile radio terminal 21 has acquired the reception statusinformation and the positional information. If a forced shutdown of usercommunication or a handover failure is used as a trigger, then mobileradio terminal 21 is unable to send the measured information toinformation collecting server 1 immediately after the trigger isdetected. In this case, mobile radio terminal 21 may send the measuredinformation after the circuit becomes available again.

Information collecting server 1 receives the measured information frommobile radio terminal 21, and records the received information in itsown memory (step 105). Actually, since information collecting server 1receives measured information similarly from a plurality of mobile radioterminals, information collecting server 1 collects reception statusinformation in various positions in coverages.

The measured information collected by information collecting server 1 isrelated to various operations of the radio communication systemdepending on trigger conditions. Consequently, not only a maprepresenting an association between positions and reception statuses,but also maps related to various statuses are obtained. For example, amap of information that is acquired when user communications areforcibly disconnected is useful for estimating an area where aradio-wave arrival status is poor. A map of information that is acquiredwhen a handover failure occurs is useful for estimating a position wherethere is a coverage interruption between radio base stations. A map ofinformation that is acquired when a throughput is lower than apredetermined threshold value is useful for estimating a position wherea communication quality is poor. A map of information that is acquiredwhen a call is made is useful for estimating a position where many usersare present.

The measuring time represented by the time information contained in themeasured information is useful to estimate a time-dependent change inthe communication status or the reception status.

Then, information collecting server 1 gives a valuable point to the userof mobile radio terminal 21, and sends valuable point informationrepresentative of a value (valuable point) given in return for theinformation provided by the user, to mobile radio terminal 21 (step106). For non-delay system operation, information collecting server 1should preferably send valuable point information is sent to mobileradio terminal 21 immediately after the measured information from mobileradio terminal 21. If a traffic buildup is to be prevented, however,information collecting server 1 may delay the timing to send valuablepoint information. For example, information collecting server 1 maycollect several items of valuable point information and thereafter sendthe collected items of valuable point information. Informationcollecting server 1 may also send collected items of valuable pointinformation late at night.

Actually, a valuable point may be given by different processes dependingon the form of the variable point. For example, if a valuable point canbe used to offset a charge to be paid for using the radio communicationsystem, then it may be recorded and managed in information collectingserver 1, a billing center (not shown), or a dedicated valuable pointmanaging server. If a valuable point is in the form of electric moneyrelated to a bank account, then the valuable point may be sent to a bankserver.

When measure information is thus collected by information collectingserver 1, core network 2 of the radio communication system uses thecollected information for the maintenance of radio base stations 11, 12,13 and for adjusting various parameters including the transmissionoutput power and the tilt angles of antennas.

According to the present embodiment, as described above, when apredetermined communication status is achieved, the mobile radioterminals of users acquire reception state information and positionalinformation, and send measured information including the reception stateinformation and the positional information to information collectingserver 1. Therefore, the communication service provider caninstantaneously obtain many items of measured information related to thecommunication status by giving inexpensive valuable points to users, andcan instantaneously and effectively perform maintenance and adjustmentsof the radio base stations with reduced man-hours and expenses.

According to the present embodiment, furthermore, since many items ofmeasured information can instantaneously be collected and reflected forsystem maintenance and adjustments, the measured information can provideoutstanding advantages while the number of users is being progressivelygrown in a radio communication system, e.g., a CDMA radio communicationsystem, where coverages change due to a load status or an interferencequantity on radio circuits when mobile radio terminals are connected.

Moreover, instantaneous and accurate system adjustments are significantin an area where many users are present. Since many items of measuredinformation of such an area are obtained, it is possible to makeinstantaneous and accurate system adjustments using many items ofmeasured information in an area where the need for system adjustments ishigh.

According to the present embodiment, measured information is acquiredonly from the mobile radio terminals of users who have consented toprovide positional information and reception status information.Therefore no information is automatically acquired from users who do notwant to send positional information and reception status information tothe communication service provider. The users are thus free from undueconcerns from the standpoint of their privacy and electric powerconsumption by their mobile radio terminals.

Another embodiment of the present invention will be described below.

A radio communication system according to the present embodiment isidentical in arrangement to the radio communication system shown in FIG.2. However, the radio communication system according to the presentembodiment operates differently from the operation sequence shown inFIG. 4 in that a trigger for mobile radio terminals 21, 22 to obtainmeasured information is given from information collecting server 1simultaneously to a plurality of mobile radio terminals.

FIG. 5 shows in block form a mobile radio terminal according to anotherembodiment of the present invention. The mobile radio terminal shown inFIG. 5 differs from the mobile radio terminal shown in FIG. 3 in that ithas trigger information reception unit 37 instead of communicationstatus acquisition unit 33.

Trigger information reception unit 37 receives trigger information frominformation collecting server 1, and sends the received triggerinformation to control unit 35. The trigger information is informationfor triggering the measurement of information. According to the presentembodiment, information collecting server 1 can send trigger informationsimultaneously to a plurality of mobile radio terminals in order tocause the mobile radio terminals to start measuring information.

Control unit 35 is triggered by the reception of trigger informationfrom information collecting server 1 to instruct reception statusacquisition unit 32 to measure a reception status, instruct positionalinformation acquisition unit 31 to measure positional information, andinstruct time information acquisition unit 34 to acquire a measuringtime, etc.

FIG. 6 shows an operation sequence of the radio communication system andthe mobile radio terminal according to the present embodiment forcollecting reception status information. In FIG. 6, operation of onlymobile radio terminal 21 and information collecting server 1 isillustrated.

Dedicated software is installed beforehand in the mobile radio terminalof a user who has consented to provide measured information includingreception status information and positional information in return forthe acquisition of a valuable point. The mobile radio terminal with thededicated software installed is used as mobile radio terminals 21, 22.

As shown in FIG. 6, information collecting server 1 sends triggerinformation simultaneously to a plurality of mobile radio terminals(step 201). For example, information collecting server 1 sends triggerinformation in a special time zone where a reception status is to beobserved, such as a time zone in which the system load is statisticallyhigh or a time zone in which the system load is statistically low. Inresponse to the trigger information, mobile radio terminal 21 measures areception status and acquires the measured reception status as receptionstatus information (step 202). At this time, mobile radio terminal 21also acquires time information.

The subsequent processing in steps 203 through 207 is the same as theprocessing in steps 103 through 107 shown in FIG. 4.

The measured information collected by information collecting server 1has been simultaneously acquired by a plurality of mobile radioterminals which have been triggered by the reception of the triggerinformation. Therefore, not only a map representing an associationbetween positions and reception statuses, but also reception statuses invarious positions in coverages at the same time are acquired. Theinformation thus acquired is useful to estimate how changes in thereception statuses in the respective positions are related.

According to the present embodiment, as described above, mobile radioterminals are triggered by trigger information sent from informationcollecting server 1 simultaneously to a plurality of mobile radioterminals, to acquire reception status information and positionalinformation, and send measured information including the reception stateinformation and the positional information to information collectingserver 1. Therefore, the communication service provider caninstantaneously obtain many items of measured information at respectivespots at the same time by giving inexpensive valuable points to users,and can instantaneously and effectively perform maintenance andadjustments of the radio base stations with reduced man-hours andexpenses.

Another embodiment of the present invention will be described below.

A radio communication system according to the present embodiment isidentical in arrangement to the radio communication system shown in FIG.2. However, the radio communication system according to the presentembodiment operates differently from the operation sequence shown inFIG. 4 in that triggers for mobile radio terminals 21, 22 to obtainmeasured information include a trigger given from information collectingserver 1 simultaneously to a plurality of mobile radio terminals, asshown in FIG. 4, and a trigger which is detected by the mobile radioterminals themselves as shown in FIG. 4.

FIG. 7 shows in block form a mobile radio terminal according to thisembodiment of the present invention. The mobile radio terminal shown inFIG. 7 differs from the mobile radio terminal shown in FIG. 3 in that ithas both communication status acquisition unit 33 and triggerinformation reception unit 37. Communication status acquisition unit 33shown in FIG. 7 is identical to communication status acquisition unit 33shown in FIG. 3, and trigger information reception unit 37 shown in FIG.7 is identical to trigger information reception unit 37 shown in FIG. 5.

When communication status information is acquired as a trigger bycommunication status acquisition unit 33 or when trigger information isreceived by trigger information reception unit 37, control unit 35 istriggered to instruct reception status acquisition unit 32,communication status acquisition unit 33, and time informationacquisition unit 34.

FIG. 8 shows an operation sequence of the radio communication system andthe mobile radio terminal according to the present embodiment forcollecting reception status information. In FIG. 8, operation of onlymobile radio terminal 21 and information collecting server 1 isillustrated.

Dedicated software is installed beforehand in the mobile radio terminalof a user who has consented to provide measured information includingreception status information and positional information in return forthe acquisition of a valuable point. The mobile radio terminal with thededicated software installed is used as mobile radio terminals 21, 22.

As shown in FIG. 8, information collecting server 1 sends triggerinformation simultaneously to a plurality of mobile radio terminals(step 301), or mobile ratio terminal 21 detects as a trigger whencommunication status information has satisfied a predetermined condition(step 302).

When either trigger is generated, mobile ratio terminal 21 measures areception status and acquires it as reception status information (step303). At this time, mobile radio terminal 21 also acquires timeinformation.

The subsequent processing in steps 304 through 308 is the same as theprocessing in steps 103 through 107 shown in FIG. 4.

The measured information collected by information collecting server 1 isrelated to various operations of the radio communication system orobtained at the same time, depending on trigger conditions.Consequently, not only a map representing an association betweenpositions and reception statuses, but also maps related to variousstatuses or maps representative of reception statuses in variouspositions in coverages at the same time are acquired.

According to the present embodiment, as described above, mobile radioterminals are triggered by a certain communication status or triggerinformation sent from information collecting server 1 simultaneously toa plurality of mobile radio terminals, to acquire reception statusinformation and positional information, and send measured informationincluding the reception state information and the positional informationto information collecting server 1. Therefore, the communication serviceprovider can instantaneously obtain many items of measured informationrelated to communication statuses and measured information at respectivespots at the same time by giving inexpensive valuable points to users,and can instantaneously and effectively perform maintenance andadjustments of the radio base stations with reduced man-hours andexpenses.

While preferred embodiments of the present invention have been describedusing specific terms, such description is for illustrative purposesonly, and it is to be understood that changes and variations may be madewithout departing from the spirit or scope of the following claims.

What is claimed is:
 1. A mobile radio terminal, comprising: a receiverconfigured to receive one or more signals from a base station; aprocessor configured to: perform measurements of a received quality ofthe one or more signals; obtain location information indicating alocation of the mobile radio terminal; and detect a handover failure bythe mobile radio terminal after or during the measurement of thereceived quality of the one or more signals; and a transmitterconfigured to transmit handover failure related information after thehandover failure detection, wherein the handover failure relatedinformation includes: a value of the received quality based on themeasurements collected by the mobile radio terminal up to a moment ofthe handover failure detection, and the location information indicatingthe location of the mobile radio terminal.
 2. The mobile radio terminalaccording to claim 1, wherein the transmitter is further configured totransmit the handover failure related information after a user of themobile radio terminal has consented to provide the handover failurerelated information.
 3. The mobile radio terminal according to claim 1,wherein the processor is configured to detect a time at which thehandover failure occurred.
 4. A base station, comprising: a transmitterconfigured to transmit one or more signals to a mobile radio terminalperforming measurements of a received quality of the one or moresignals; and a receiver configured to receive handover failure relatedinformation from the mobile radio terminal after a handover failuredetection is detected by the mobile radio terminal after or during themeasurement of the received quality of the one or more signals, whereinthe handover failure related information includes: a value of thereceived quality based on the measurements collected by the mobile radioterminal up to a moment of the handover failure detection, and locationinformation indicating a location of the mobile radio terminal obtainedby the mobile radio terminal.
 5. The base station according to claim 4,wherein the handover failure related information are transmitted fromthe mobile radio terminal after a user of the mobile radio terminal hasconsented to provide the position information.
 6. A method of a mobileradio terminal, the method comprising: receiving one or more signalsfrom a base station; performing measurements of a received quality ofthe one or more signals; obtaining location information indicating alocation of the mobile radio terminal; detecting a handover failure bythe mobile terminal after or during the measurement of the receivedquality of the one or more signals; and transmitting handover failurerelated information after the handover failure detection, wherein thehandover failure related information includes: a value of the receivedquality based on the measurements collected by the mobile radio terminalup to a moment of the handover failure detection, and the locationinformation indicating the location of the mobile radio terminal.
 7. Themethod according to claim 6, wherein the handover failure relatedinformation is transmitted after a user of the mobile radio terminal hasconsented to provide the handover failure related information.
 8. Themethod according to claim 6, further comprising transmitting thehandover failure related information to an information collectingserver.
 9. The method according to claim 6, further comprising:detecting a time at which the handover failure occurred; andtransmitting the time information to a base station along with thehandover failure related information.
 10. A non-transitory storagemedium tangibly embodying a set of computer-readable instructionscausing a processor in a mobile radio terminal to execute the method ofclaim
 6. 11. A method of a base station, the method comprising:transmitting one or more signals to a mobile radio terminal performingmeasurements of a received quality of the one or more signals; andreceiving handover failure related information from the mobile radioterminal after a handover failure detection that is detected by themobile radio terminal after or during the measurement of the receivedquality of the one or more signals, wherein the handover failure relatedinformation includes: a value of the received quality based on themeasurements collected by the mobile radio terminal up to a moment ofthe handover failure detection, and location information indicating alocation of the mobile radio terminal as obtained by the mobile radioterminal.
 12. The method according to claim 11, wherein the handoverfailure related information is transmitted after a user of the mobileradio terminal has consented to provide the handover failure relatedinformation.
 13. The method according to claim 11, wherein timeinformation of the handover failure is also received by the basestation.
 14. The method according to claim 11, further comprisingtransmitting the handover failure related information to an informationcollecting server.
 15. A non-transitory storage medium tangiblyembodying a set of computer-readable instructions causing a processor inthe base station to execute the method of claim 11.